TY - JOUR TI - Structural development and dorsoventral maturation of the medial entorhinal cortex AU - Ray, Saikat AU - Brecht, Michael A2 - Eichenbaum, Howard VL - 5 PY - 2016 DA - 2016/04/02 SP - e13343 C1 - eLife 2016;5:e13343 DO - 10.7554/eLife.13343 UR - https://doi.org/10.7554/eLife.13343 AB - We investigated the structural development of superficial-layers of medial entorhinal cortex and parasubiculum in rats. The grid-layout and cholinergic-innervation of calbindin-positive pyramidal-cells in layer-2 emerged around birth while reelin-positive stellate-cells were scattered throughout development. Layer-3 and parasubiculum neurons had a transient calbindin-expression, which declined with age. Early postnatally, layer-2 pyramidal but not stellate-cells co-localized with doublecortin – a marker of immature neurons – suggesting delayed functional-maturation of pyramidal-cells. Three observations indicated a dorsal-to-ventral maturation of entorhinal cortex and parasubiculum: (i) calbindin-expression in layer-3 neurons decreased progressively from dorsal-to-ventral, (ii) doublecortin in layer-2 calbindin-positive-patches disappeared dorsally before ventrally, and (iii) wolframin-expression emerged earlier in dorsal than ventral parasubiculum. The early appearance of calbindin-pyramidal-grid-organization in layer-2 suggests that this pattern is instructed by genetic information rather than experience. Superficial-layer-microcircuits mature earlier in dorsal entorhinal cortex, where small spatial-scales are represented. Maturation of ventral-entorhinal-microcircuits – representing larger spatial-scales – follows later around the onset of exploratory behavior. KW - medial entorhinal cortex KW - parasubiculum KW - pyramidal neurons KW - calbindin patches KW - doublecortin KW - immature neurons JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -